Photoresist polymers and photoresist compositions

ABSTRACT

A photoresist polymer comprising a first repeating unit including a halogen donor group and a second repeating unit including a protecting group connected by a sulfide bond.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application based on pending application Ser. No.14/886,155 filed Oct. 19, 2015, the entire contents of which are herebyincorporated by reference.

This application claims priority under 35 USC §119 to Korean PatentApplication No. 10-2014-0167424, filed on Nov. 27, 2014, the contents ofwhich are incorporated by reference herein in their entirety.

FIELD

Example embodiments relate to photoresist polymers, photoresistcompositions, methods of forming patterns and methods of manufacturingsemiconductor devices. More particularly, example embodiments relate tophotoresist polymers including different repeating units, photoresistcompositions including the photoresist polymers, and methods of formingpatterns and methods of manufacturing semiconductor devices using thephotoresist polymers.

BACKGROUND

A photolithography process may be utilized for a formation of variouspatterns included in a semiconductor device. For example, a photoresistlayer may be divided into an exposed portion and a non-exposed portionby, e.g., an exposure process, and the exposed portion may be removed bya developing process to form a photoresist pattern. The object layer maybe patterned using the photoresist pattern as an etching mask to form adesired pattern.

However, an intermediate component such as an acid may be generated fromthe exposure process, and a resolution of the photolithography processmay be deteriorated by the intermediate.

SUMMARY

Example embodiments of the present inventive concepts provide aphotoresist polymer having an improved resolution.

Example embodiments of the present inventive concepts provide aphotoresist composition including a photoresist polymer of the presentinventive concepts.

Example embodiments of the present inventive concepts provide a methodof forming a pattern using a photoresist polymer of the presentinventive concepts.

Example embodiments of the present inventive concepts provide a methodof manufacturing a semiconductor device using a photoresist polymer ofthe present inventive concepts.

According to example embodiments of the present inventive concepts,there is provided a photoresist polymer. The photoresist polymerincludes a first repeating unit including a halogen donor group, and asecond repeating unit including a protecting group connected by asulfide bond.

In example embodiments, the halogen donor group may include aheterocyclic compound having a nitrogen-halogen bond.

In example embodiments, the halogen donor group may include at least oneof N-iodosuccinimide (NIS), N-bromosuccinimide (NBS),N-chlorosuccinimide (NCS), N-iodophthalimide (NIPI), N-bromophthalimide(NBPI) and N-chlorophthalimide (NCPI).

In example embodiments, the polymer may include a structure that isrepresented by Chemical Formula 1 or Chemical Formula 2.

In Chemical Formulae 1 and 2, R₁ and R₄ may be independently a divalentgroup selected from styrene, hydroxystyrene, acrylate, C₁-C₆ alkylene,arylene, carbonyl, oxy, C₆-C₃₀ aliphatic ester, C₆-C₃₀ unsaturatedaliphatic group or a combination thereof. R₂ may be hydrogen or a C₁-C₂₀alkyl group. R₃ may be a C₆-C₃₀ aromatic group or a C₁-C₂₀ alkyl group.X may represent chlorine (Cl), bromine (Br) or iodine (I). Each a and bmay represent a mole ratio ranging from about 0.4 to about 0.6, and asum of a and b may be 1.

In example embodiments, the polymer may include a structure that isrepresented by Chemical Formula 3 or Chemical Formula 4.

In Chemical Formulae 3 and 4, n may be an integer ranging from 100 to10,000.

According to example embodiments of the present inventive concepts,there is provided a photoresist composition. The photoresist compositionincludes a polymer in which a first repeating unit including a halogendonor group and a second repeating unit including a protecting groupconnected by a sulfide bond are polymerized, and a solvent.

In example embodiments, the polymer may include a structure that isrepresented by the above Chemical Formula 1 or Chemical Formula 2.

In example embodiments, the photoresist composition may further includea photoacid generator.

According to example embodiments of the present inventive concepts,there is provided a method of forming a pattern. In the method, aphotoresist layer is formed on an object layer. The photoresist layerincludes a polymer in which a first repeating unit including a halogendonor group and a second repeating unit including a protecting groupconnected by a sulfide bond are polymerized. An exposure process isperformed on the photoresist layer such that the photoresist layer isdivided into an exposed portion and a non-exposed portion. The exposedportion of the photoresist layer is removed to form a photoresistpattern.

In example embodiments, a halonium ion or a halogen radical may begenerated from the halogen donor group by the exposure process.

In example embodiments, the protecting group may be separated from thesecond repeating unit by the halonium ion or the halogen radical.

In example embodiments, the exposure process may be performed by a lightsource including ArF, KrF, an electron beam, I-line and/or extremeultraviolet (EUV).

In example embodiments, the photoresist layer may be formed by coating aphotoresist composition on the object layer. The photoresist compositionmay include the polymer, a solvent and a photoacid generator.

In example embodiments, a proton (FE) generated from the photoacidgenerator may be trapped by the halogen donor group.

In example embodiments, the halogen donor group may include anitrogen-halogen bond and a carbonyl bond. The proton may be trapped bythe carbonyl bond so that a halonium ion may be generated from thenitrogen-halogen bond.

In example embodiments, the exposed portion may be more hydrophilic thanthe non-exposed portion.

In example embodiments, the exposed portion may include an acetalstructure to which a hydroxyl group may be combined.

In example embodiments, the exposed portion may be selectively removedusing a developing solution.

In example embodiments, the polymer may be represented by a structure asprovided by above Chemical Formula 1 or Chemical Formula 2.

In example embodiments, the object layer may be patterned using thephotoresist pattern as an etching mask.

According to example embodiments of the present inventive concepts,there is provided a method of forming a pattern. In the method, aphotoresist layer is formed on an object layer. The photoresist layerincludes a polymer in which a first unit including a nitrogen-halogenbond and a second unit including a sulfide bond are alternatelypolymerized. A selective exposure process is performed on thephotoresist layer so that an active halogen is generated from thenitrogen-halogen bond, and the active halogen is transferred to thesulfide bond. An exposed portion of the photoresist layer is removed toform a photoresist pattern.

In example embodiments, the first unit may include N-iodosuccinimide(NIS), N-bromosuccinimide (NBS), N-chlorosuccinimide (NCS),N-iodophthalimide (NIPI), N-bromophthalimide (NBPI) and/orN-chlorophthalimide (NCPI).

In example embodiments, the second unit may have a structure that is berepresented by Chemical Formula 5.

In Chemical Formula 5, R₁ may be a divalent group including styrene,hydroxystyrene, acrylate, C₁-C₆ alkylene, arylene, carbonyl, oxy, C₆-C₃₀aliphatic ester, C₆-C₃₀ unsaturated aliphatic group or a combinationthereof. R₂ may be hydrogen or a C₁-C₂₀ alkyl group. R₃ may be a C₆-C₃₀aromatic group or a C₁-C₂₀ alkyl group.

In example embodiments, —SR₃ included in the second unit may beseparated from the second unit by the active halogen.

In example embodiments, the exposed portion may be converted to ahydrophilic pattern.

According to example embodiments of the present inventive concepts,there is provided a method of manufacturing a semiconductor device. Inthe method, a plurality of active patterns defined by an isolation layeris formed on a substrate. A gate structure is formed on at least one ofthe plurality of active patterns. An impurity region is formed at anupper portion of the at least one active pattern adjacent to the gatestructure. An insulating interlayer covering the isolation layer and theat least one active pattern is formed. A photoresist layer is formed onthe insulating interlayer. The photoresist layer includes a polymer inwhich a first repeating unit including a halogen donor group, and asecond repeating unit including a protecting group connected by asulfide bond are polymerized. An exposure process is performed on thephotoresist layer such that the photoresist layer is divided into anexposed portion and a non-exposed portion. The exposed portion of thephotoresist layer is removed to form a photoresist pattern. Theinsulating interlayer is partially removed using the photoresist patternas an etching mask to form a contact hole through which the impurityregion is exposed. A conductive contact electrically connected to theimpurity region is formed in the contact hole.

In example embodiments, the gate structure may be at least partiallyburied in the plurality of active patterns and the isolation layer.

In example embodiments, in the formation of the impurity region, a firstimpurity region may be formed between the gate structures, and a secondimpurity region may be formed at a peripheral portion of the at leastone active pattern. The second impurity region may be exposed throughthe contact hole.

In example embodiments, a capacitor may be further formed on theconductive contact.

In example embodiments, the polymer may have a structure that is berepresented by the above Chemical Formula 1 or Chemical Formula 2.

According to example embodiments of the present inventive concepts,there is provided a method of forming a pattern, the method comprisingforming a photoresist layer on an object layer, the photoresist layerincluding a polymer that comprises a first repeating unit including ahalogen donor group, and a second repeating unit including a protectinggroup connected by a sulfide bond; generating a halonium ion or ahalogen radical from a first repeating unit of the polymer; and removingthe protecting group from a second repeating unit of the polymer.

The first repeating unit of the polymer may include a heterocycliccompound having a nitrogen-halogen bond. In some embodiments, the firstrepeating unit of the photoresist polymer may include at least onemoiety selected from N-iodosuccinimide (NIS), N-bromosuccinimide (NBS),N-chlorosuccinimide (NCS), N-iodophthalimide (NIPI), N-bromophthalimide(NBPI) and N-chlorophthalimide (NCPI).

In some embodiments, the polymer may include a structure that isrepresented by Chemical Formula 1 or Chemical Formula 2 as providedabove. In some embodiments, the polymer may include a structure that isrepresented by Chemical Formula 3 or Chemical Formula 4.

In some embodiments, the halonium ion or the halogen radical may reactwith a sulfur atom in the sulfide bond to remove the protecting groupfrom the second repeating unit of the polymer.

In some embodiments, the protecting group from the second repeating unitof the polymer may be replaced with a hydroxyl group.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and advantages of the presentinventive concepts will become more apparent in view of the attacheddrawings and accompanying detailed description. The drawings providedherein represent non-limiting, example embodiments according to variousembodiments of the present inventive concepts.

FIGS. 1 to 6 are cross-sectional views illustrating a method of forminga pattern according to various embodiments of the present inventiveconcepts.

FIGS. 7 to 14 are cross-sectional views illustrating a method of forminga pattern according to further embodiments of the present inventiveconcepts.

FIGS. 15 to 25 are top plan views and cross-sectional views illustratinga method of manufacturing a semiconductor device according to variousembodiments of the present inventive concepts.

DESCRIPTION OF EMBODIMENTS

Various example embodiments are described below with reference to theaccompanying drawings, in which some example embodiments are shown. Manydifferent forms and embodiments are possible without deviating from thespirit and teachings of this disclosure and so the disclosure should notbe construed as limited to the example embodiments set forth herein.Rather, these example embodiments are provided so that this disclosurewill be thorough and complete, and will convey the scope of thedisclosure to those skilled in the art. In the drawings, the sizes andrelative sizes of layers and regions may be exaggerated for clarity.Like reference numbers refer to like elements throughout the disclosure.

The terminology used herein is for the purpose of describing particularexample embodiments only and is not intended to be limiting of theembodiments. As used herein, the singular forms “a,” “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises,” “comprising,” “includes,” and/or “including,” when used inthis specification, specify the presence of the stated features, steps,operations, elements, and/or components, but do not preclude thepresence or addition of one or more other features, steps, operations,elements, components, and/or groups thereof.

It will be understood that when an element is referred to as being“coupled,” “connected,” or “responsive” to, or “on,” another element, itcan be directly coupled, connected, or responsive to, or on, the otherelement, or intervening elements may also be present. In contrast, whenan element is referred to as being “directly coupled,” “directlyconnected,” or “directly responsive” to, or “directly on,” anotherelement, there are no intervening elements present. As used herein theterm “and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, third,fourth etc. may be used herein to describe various elements, components,regions, layers and/or sections, these elements, components, regions,layers and/or sections should not be limited by these terms. These termsare only used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present inventive concept.

Spatially relative terms, such as “beneath,” “below,” “lower,” “above,”“upper,” and the like, may be used herein for ease of disclosure todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the term “below” can encompass both an orientation ofabove and below. The device may be otherwise oriented (rotated 90degrees or at other orientations) and the spatially relative descriptorsused herein may be interpreted accordingly.

Example embodiments of the present inventive concepts are describedherein with reference to cross-sectional illustrations that areschematic illustrations of idealized example embodiments (andintermediate structures). As such, variations from the shapes of theillustrations as a result, for example, of manufacturing techniquesand/or tolerances, are to be expected. Thus, example embodiments of thepresent inventive concepts should not be construed as limited to theparticular shapes of regions illustrated herein but are to includedeviations in shapes that result, for example, from manufacturing. Forexample, an implanted region illustrated as a rectangle may actuallyhave rounded or curved features and/or a gradient of implantconcentration at its edges rather than a binary change from implanted tonon-implanted region. Likewise, a buried region formed by implantationmay result in some implantation in the region between the buried regionand the surface through which the implantation takes place. Thus, theregions illustrated in the figures are schematic in nature and theirshapes are not intended to illustrate the actual shape of a region of adevice and are not intended to limit the scope of the exampleembodiments.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which these present inventive conceptsbelong. It will be further understood that terms, such as those definedin commonly used dictionaries, should be interpreted as having a meaningthat is consistent with their meaning in the context of the relevant artand/or the present specification and will not be interpreted in anidealized or overly formal sense unless expressly so defined herein.

Photoresist Polymers

A photoresist polymer in accordance with example embodiments may includea first repeating unit and a second repeating unit that may bealternately and repeatedly propagated in a backbone chain.

The backbone chain may include a carbon chain, which may be included ina photoresist material. For example, the backbone chain may include apolymer chain such as novolak, polystyrene, polyhydroxystyrene (PHS),polyacrylate, polymethacrylate, polyvinyl ester, polyvinyl ether,polyolefin, polynorbornene, polyester, polyamide, polycarbonate or thelike. In some embodiments, novolak, polystyrene, PHS or polyacrylate maybe used as the backbone chain.

The first repeating unit may include a halogen donor group.

In example embodiments, the halogen donor group may include anitrogen-halogen bond having a high photochemical reactivity. Forexample, the nitrogen-halogen bond may be decomposed by an ultraviolet(UV) exposure process so that an active halogen such as a halonium ionor a halogen radical may be generated from the halogen donor group.

In some embodiments, the halogen donor group may include a heterocycliccompound containing nitrogen. For example, the halogen donor group mayinclude N-iodosuccinimide (NIS), N-bromosuccinimide (NBS),N-chlorosuccinimide (NCS), N-iodophthalimide (NIPI), N-bromophthalimide(NBPI) or N-chlorophthalimide (NCPI). Thus, the photoresist polymer mayinclude at least one moiety selected from NIS, NBS, NCS, NIPI, NBPI, andNCPI. “Moiety” or “moieties,” as used herein, refer to a portion of amolecule, such as a portion of a polymer, typically having a particularfunctional or structural feature. For example, a moiety may include afunctional group off a backbone chain of a polymer and/or a functionalgroup that is part of a side chain of polymer.

In example embodiments, the second repeating unit may include aprotecting group connected by a sulfide bond. Thus, the protecting groupmay be attached to the second repeating unit of the photoresist polymervia a sulfide bond. The active halogen separated from the firstrepeating unit may be transferred to a neighboring second repeatingunit. Accordingly, the sulfide bond may be dissociated so that theprotecting group may be separated from the second repeating unit.

In some embodiments, the photoresist polymer may include a structurerepresented by Chemical Formula 1 or Chemical Formula 2.

In Chemical Formulae 1 and 2, R₁ and R₄ may each independently be adivalent group selected from styrene, hydroxystyrene, acrylate, C₁-C₆alkylene, arylene, carbonyl, oxy, C₆-C₃₀ aliphatic ester, C₆-C₃₀unsaturated aliphatic group or a combination thereof. R₁ and R₄ may bethe same as or different from each other. In some embodiments, R₁ and/orR₄ in one repeating unit may be the same as or different from R₁ and/orR₄ in another repeating unit. R₂ may be hydrogen or a C₁-C₂₀ alkylgroup, and R₃ may be a C₆-C₃₀ aromatic group or a C₁-C₂₀ alkyl group. Xmay represent chlorine (Cl), bromine (Br) or iodine (I). Each a and bmay represent a mole ratio. In some embodiments, each a and b may be ina range of about 0.4 to about 0.6, and a sum of a and b may be 1.

In the above Chemical Formulae 1 and 2, a right unit represented by “b”may correspond to the first repeating unit, and a left unit representedby “a” may correspond to the second repeating unit.

In some embodiments, the first and second repeating units may bealternately repeated in the backbone chain. In this case, the first andsecond repeating units may be combined in a ratio of 1:1 to form onepolymerized repeating unit, and the polymerized repeating units may berepeated in the backbone chain.

Accordingly, the photoresist polymer chain may include a structurerepresented by the following Chemical Formula 3 or Chemical Formula 4.

In some embodiments, in Chemical Formulae 3 and/or 4, n may be aninteger in a range of 100 to 10,000.

As described above, the active halogen such as a halonium ion (X⁺) or ahalogen radical (X•) may be generated from an imide nitrogen of thehalogen donor group included in the first repeating unit. The activehalogen may attack a sulfur atom present in the second repeating unit sothat the protecting group (—SR₃) may be separated from the second unit.A site from which the protecting group is removed may be replaced with ahydroxyl group. Thus, a portion of the photoresist polymer from whichthe protecting group is separated or removed may be substantiallyhydrophilic.

In example embodiments, the photoresist polymer may be utilized as apositive type photoresist material. In this case, a portion of thephotoresist polymer from which the protecting group is separated may beremoved by a developing solution.

Photoresist Compositions

A photoresist composition in accordance with example embodiments mayinclude a photoresist polymer of the present inventive concepts and asolvent.

As described above, the photoresist polymer may include a firstrepeating unit containing a halogen donor group and a second repeatingunit containing a protecting group connected by a sulfide bond, whichmay be repeated in a backbone chain.

In some embodiments, the photoresist polymer may have a structure thatmay be represented by the above-mentioned Chemical Formula 1 or ChemicalFormula 2. In some embodiment, the photoresist polymer may have astructure that may be represented by the above-mentioned ChemicalFormula 3 or Chemical Formula 4.

The solvent may include an organic solvent having a solubility suitablefor a polymer material, and a coatability suitable for a formation of auniform photoresist layer. Example solvents may include, but are notlimited to, cyclohexanone, cyclopentanone, tetrahydrofuran (THF),dimethylformamide, propylene glycol monomethyl ether acetate (PGMEA),ethyl lactate, methyl ethyl ketone, benzene or toluene. These may beused alone or in combination. In some embodiments, 1, 2, 3, 4, or moresolvent(s) may be present in a photoresist composition.

In example embodiments, the photoresist composition may include apositive type photoresist. For example, a photoresist layer may beformed using the photoresist composition, and an exposure process may beperformed on the photoresist layer. A polymer structure of an exposedportion may be modified to have a hydrophilicity and/or a solubilitygreater than those of a non-exposed portion. The exposed portion may beremoved by a developing solution so that a photoresist pattern may beobtained.

An active halogen may be generated from the halogen donor group in theexposed portion, and the sulfide bond contained in the second repeatingunit of the exposed portion may be dissociated by the active halogen sothat the protecting group may be departed or removed from the secondrepeating unit. Accordingly, the hydrophilicity and/or the solubility ofthe exposed portion may be increased.

In some embodiments, the photoresist composition may further include aphotoacid generator (PAG). A proton (H⁺) generated from the PAG may betrapped by the halogen donor group. As a result, a halonium ion (X⁺) maybe created from a nitrogen-halogen bond so that the protecting group ofthe second repeating unit may be separated or removed. In this case, thePAG may serve as a catalyst for creating the halonium ion.

The PAG may include any compounds capable of generating an acid by anexposure process. For example, the PAG may include, but is not limitedto, an onium salt, an aromatic diazonium salt, a sulfonium salt, atriarylsulfonium salt, a diarylsulfonium salt, a monoarylsulfonium salt,an iodonium salt, a diaryliodonium salt, nitrobenzyl ester, disulfone,diazo-disulfone, sulfonate, trichloromethyl triazine,N-hydroxysuccinimide triflate, or the like. These may be used alone orin combination. In some embodiments, 1, 2, 3, 4, or more PAG(s) may bepresent in a photoresist composition.

In some embodiments, the active halogen may be created only through aphotochemical reaction by an exposure process without using a PAG. Inthis case, the active halogen may include a halogen radical. In someembodiments, the photoresist composition may further include asensitizer for facilitating the photochemical reaction. An amount ofphotons may be amplified by the sensitizer, and thus a sufficient amountof the active halogen may be obtained.

Example sensitizers include, but are not limited to, benzophenone,benzoyl, thiophene, naphthalene, anthracene, phenanthrene, pyrene,coumarin, thioxantone, acetophenone, naphtoquinone, anthraquinone, orthe like. These may be used alone or in combination. In someembodiments, 1, 2, 3, 4, or more sensitizers(s) may be present in aphotoresist composition.

The photoresist composition may further include an additive forimproving chemical and/or physical properties of the composition. Theadditive may include, e.g., a leveling agent, a viscosity modifier, asurfactant, and/or the like. In some embodiments, 1, 2, 3, 4, or moreadditive(s) may be present in a photoresist composition.

Methods of Forming Patterns

FIGS. 1 to 6 are cross-sectional views illustrating a method of forminga pattern in accordance with example embodiments of the presentinventive concepts. For example, FIGS. 1 to 6 illustrate the method offorming patterns utilizing a photoresist polymer or photoresistcomposition of the present inventive concepts.

Referring to FIG. 1, an object layer 110 may be formed on a substrate100. The substrate 100 may include a silicon substrate, a germaniumsubstrate, a silicon-germanium substrate, a silicon-on-insulator (SOI)substrate or a germanium-on-insulator (GOI) substrate. In someembodiments, the substrate 100 may include a group III-V compound suchas GaP, GaAs or GaSb.

An image may be transferred from a photoresist pattern to the objectlayer 110 so that the object layer 110 may be converted to apredetermined pattern. In some embodiments, the object layer 110 may beformed of an insulative material such as silicon oxide, silicon nitrideor silicon oxynitride. In some embodiments, the object layer 110 may beformed of a conductive material such as a metal, a metal nitride, ametal silicide or a metal silicide nitride. In some embodiments, theobject layer 110 may be formed of a semiconductor material such aspolysilicon.

The object layer 110 may be formed by at least one process of a chemicalvapor deposition (CVD) process, a plasma enhanced chemical vapordeposition (PECVD) process, a low pressure chemical vapor deposition(LPCVD) process, a high density plasma chemical vapor deposition(HDP-CVD) process, a spin coating process, a sputtering process, anatomic layer deposition (ALD) process, and a physical vapor deposition(PVD) process.

Referring to FIG. 2, an anti-reflective layer 120 and a photoresistlayer 130 may be sequentially formed on the object layer 110.

The anti-reflective layer 120 may be formed using an aromatic organiccomposition such as a phenol resin or a novolak resin, or an inorganicmaterial such as silicon oxynitride. The anti-reflective layer 120 maybe formed by, e.g., a spin coating process, a dip coating process or aspray coating process. The anti-reflective layer 120 may also serve as aplanarization layer. In some embodiments, formation of theanti-reflective layer 120 may be omitted.

The photoresist layer 130 may be formed using a photoresist compositionaccording to the present inventive concepts. As described above, thephotoresist composition may include a photoresist polymer and a solvent.The photoresist polymer may include a first repeating unit containing ahalogen donor group and a second repeating unit containing a protectinggroup connected by a sulfide bond, which may be repeated in the backbonechain of the photoresist polymer. The photoresist composition mayoptionally include a PAG. In some embodiments, the photoresistcomposition may optionally include a sensitizer.

In some embodiments, a first repeating unit including a nitrogen-halogenbond, and a second repeating unit including a sulfide bond may bealternately polymerized to form the photoresist polymer.

For example, the first unit may include NIS, NBS, NCS, NIPI, NBPI orNCPI.

The second unit may be represented by the following Chemical Formula 5.

In Chemical Formula 5, R₁, R₂ and R₃ may be substantially the same asthose defined in the above Chemical Formulae 1 to 4.

In some embodiments, the photoresist polymer may have a structure thatmay be represented by the above Chemical Formula 1 or Chemical Formula2. In an embodiment, the photoresist polymer may have a structure thatmay be represented by the above Chemical Formula 3 or Chemical Formula4.

The photoresist layer 130 may be formed by, e.g., a spin coatingprocess, a dip coating process or a spray coating process. In someembodiments, the photoresist composition may be coated to form apreliminary photoresist layer, and the preliminary photoresist layer maybe cured by, e.g., a baking process to form the photoresist layer 130.

Referring to FIG. 3, an exposure process may be performed on thephotoresist layer 130.

In some embodiments, an exposure mask 140 may be placed on thephotoresist layer 130, and a light may be irradiated through an openingor a transmission portion included in the exposure mask 140.Non-limiting examples of a light source used in the exposure process mayinclude ArF, KrF, an electron beam, I-line or extreme ultraviolet (EUV).

The photoresist layer 130 may be divided into an exposed portion 133 anda non-exposed portion 135. In some embodiments, a chemical structure inthe exposed portion 133 may be modified through a mechanism shown by thefollowing Reaction Scheme 1 or Reaction Scheme 2.

For example, according to Reaction Scheme 1, the PAG may be included inthe photoresist composition. NIS may be used as the halogen donor groupof the first repeating unit, and R₃ of the second repeating unit (seeChemical Formulae 1 to 5) may be a benzene group.

Referring to Reaction Scheme 1, the photoresist layer 130 may besubstantially non-polar and/or hydrophobic before an exposure process.In operation S10, the exposure process may be initiated in the presenceof a PAG, and a proton (i.e., an acid, H⁺) may be generated from the PAGin the exposed portion 133. The proton may be trapped by NIS whichserves as the halogen donor group of the first repeating unit. Thus, theproton may not diffuse into the non-exposed portion 135.

For example, the proton may be combined with a carbonyl oxygen of NIS sothat iodine (I) may be separated from a nitrogen atom of NIS. Thus, theproton may react with a halogen donor group present in the exposedportion 133 such that the proton is not available to diffuse into thenon-exposed portion 135.

Accordingly, in operation S12, an iodine cation as a halonium ion may begenerated from the halogen donor group. The iodine cation may betransferred to the neighboring second repeating unit. The transferrediodine cation may be combined with a sulfur atom included in theprotecting group of the second repeating unit.

In operation S14, after the combination of the sulfur atom and theiodine cation, a positive charge may be created at the sulfur atom, andan unshared electron pair in an adjacent oxygen atom may be moved sothat dissociation of the sulfide bond may be initiated.

In operation S16, the sulfide bond may be completely dissociated so thatthe protecting group may be separated from the second repeating unit. Insome embodiments, a hydroxyl group may be combined at a site from whichthe protecting group is removed. The hydroxyl group may be providedfrom, e.g., the solvent of the photoresist composition or a developingsolution used in a subsequent developing process.

Accordingly, the second repeating unit in the exposed portion 133 may bemodified to include, e.g., an acetal structure, and the first repeatingunit may also be modified to include a hydroxyl group. Therefore, theexposed portion 133 may be converted to a pattern which may be polarand/or hydrophilic.

According to the mechanism described with reference to Reaction Scheme1, the proton or the acid generated from the PAG may be trapped in thefirst repeating unit, and may only serve as a catalyst for thegeneration of a halonium ion. Thus, the proton or the acid may notdiffuse into the non-exposed portion 135. Additionally, a halonium ioncreated from the first repeating unit may be reacted with the sulfidebond in the second repeating unit substantially in a ratio of 1:1. Thus,the halonium ion may not be diffused into the non-exposed portion 135,and may be selectively reacted in the exposed portion 133.

The halonium ion may have a relatively large dimension, and thus may berelatively free from diffusing into the non-exposed portion 135.

For example, according to Reaction Scheme 2, PAG may be excluded fromthe photoresist composition. NIS may be used as the halogen donor groupin the first repeating unit, and R₃ of the second repeating unit (seeChemical Formulae 1 to 5) may be a benzene group.

Referring to Reaction Scheme 2, the photoresist layer 130 may besubstantially non-polar and/or hydrophobic before an exposure process.

For example, when the exposure process may be initiated using an EUVsource, a photochemical reaction may occur by photons in operation S20so that a nitrogen-iodine bond included in NIS (i.e., the halogen donorgroup) may be dissociated.

In some embodiments, the photoresist composition may include asensitizer. Thus, an amount or the number of the photons produced by theexposure process may be increased.

As the nitrogen-iodine bond is dissociated, an iodine radical may becreated from NIS in operation S22. A nitrogen atom in NIS may be alsoradicalized. The iodine radical may be transferred to the neighboringsecond repeating unit. The transferred iodine radical may attack asulfur atom included in the protecting group of the second repeatingunit.

In operation S24, after combination of the sulfur atom and the iodineradical, the sulfur atom may be radicalized to form a positive charge,and an unshared electron pair included in an adjacent oxygen atom may bemoved so that dissociation of the sulfide bond may be initiated.Further, a double bond may be created by an electron transfer betweenthe nitrogen and carbonyl oxygen included in NIS so that carbonyl oxygenmay be radicalized.

In operation S26, the sulfide bond may be completely dissociated so thatthe protecting group may be separated from the second repeating unit,and a double bond may be created at a site from which the protectinggroup is removed. A water molecule included in the solvent of thephotoresist composition or the developing solution may be combined atthe site.

In operation S28, the second repeating unit of the exposed portion 133may be modified to include, e.g., an acetal structure, and the firstrepeating unit may also be modified to include a hydroxyl group.Therefore, the exposed portion 133 may be converted to a pattern whichmay be polar or hydrophilic.

According to the mechanism described with reference to Reaction Scheme2, the reaction between the first and second repeating units may bederived only through the exposure process without the involvement of aPAG. Thus, an exposure process that may be completely free of an aciddiffusion or a proton diffusion may be realized.

Referring to FIG. 4, the exposed portion 133 of the photoresist layer130 may be selectively removed by, e.g., a developing process.Accordingly, a photoresist pattern 150 may be defined by the non-exposedportion 135 remaining on the object layer 110 and/or the anti-reflectivelayer 120.

For example, an alcohol-based solution or a hydroxide-based solutionsuch as tetra methyl ammonium hydroxide (TMAH) may be used as thedeveloping solution. As described above, the exposed portion 133 may beconverted to a pattern which may be polar or hydrophilic relative to thenon-exposed portion 135. Therefore, the exposed portion 133 may beselectively removed by a developing solution such as TMAH.

In a comparative example, while performing an exposure process in whicha chemically amplified resist (CAR) system using a PAG is implemented,an acid may diffuse into the non-exposed portion 135 and increase asurface roughness of the photoresist pattern 150. The non-exposedportion 135 may also be damaged by the acid, and thus the photoresistpattern 150 having desired width and/or pitch may not be obtained. As acritical dimension of the photoresist pattern 150 or a target patternformed by a photolithography process is decreased, a pattern damage bythe acid diffusion may be exacerbated.

According to example embodiments, acid from a PAG may be excluded. Insome embodiments, acid from the PAG may be trapped by the halogen donorgroup included in the exposed portion 133, and may only serve as acatalyst for generating the halonium ion. Thus, polar and/or hydrophilicproperties of the exposed portion 133 may be achieved substantially onlyby a reaction between an active halogen and the protecting group.Therefore, a photolithography process system which may be substantiallyfree of pattern damage caused by an irregular acid diffusion may berealized. Further, a photoresist pattern 150 and a target pattern havinga desired fine width and/or pitch may be precisely formed.

Referring to FIG. 5, the anti-reflective layer 120 and the object layer110 may be etched using the photoresist pattern 150 as an etching mask.Accordingly, an anti-reflective layer pattern 125 and an object layerpattern 115 may be formed between the photoresist pattern 150 and thesubstrate 100.

The etching process may include a dry etching process or a wet etchingprocess properly selected in consideration of an etching selectivitybetween the photoresist pattern 150 and the object layer 110.

In some embodiments, the dry etching process may include a plasmaetching process.

In some embodiments, a proper etchant solution such as fluoric acid,phosphoric acid, sulfuric acid or peroxide may be selected depending ona material included in the object layer 110.

Referring to FIG. 6, the photoresist pattern 150 and the anti-reflectivelayer pattern 125 may be removed such that the object layer pattern 115may remain on the substrate 100.

In some embodiments, the photoresist pattern 150 and the anti-reflectivelayer pattern 125 may be removed by an ashing process and/or a stripprocess. In some embodiments, the photoresist pattern 150 and theanti-reflective layer pattern 125 may be removed by a planarizationprocess, e.g., a chemical mechanical polish (CMP) process.

If the object layer 110 includes a conductive material, the object layerpattern 115 may serve as a wiring, a contact, a pad, a plug, aninterconnection structure, or the like of a semiconductor device.

If the object layer 110 includes an insulative material, the objectlayer pattern 115 may serve as a predetermined insulation pattern, e.g.,an insulating interlayer pattern, a filling insulation pattern, or thelike. In some embodiments, a portion of the object layer 110 removed bythe above-mentioned photolithography process may be converted into acontact hole, an opening or a trench of the insulation pattern.

FIGS. 7 to 14 are cross-sectional views illustrating a method of forminga pattern in accordance with the present inventive concepts. Forexample, FIGS. 7 to 14 illustrate a method of forming a conductivepattern utilizing the above-mentioned photoresist polymer or thephotoresist composition.

Detailed descriptions on processes and/or materials substantially thesame as or similar to those illustrated with reference to FIGS. 1 to 6are omitted herein.

Referring to FIG. 7, a lower contact 215 extending through a lowerinsulation layer 210 may be formed. A plurality of the lower contacts215 may be formed in the lower insulation layer 210.

In some embodiments, the lower insulation layer 210 may be formed on apassivation layer 200, and a contact hole extending through the lowerinsulation layer 210 and the passivation layer 200 may be formed. Thelower contact 215 may be formed by filling a conductive layer in thecontact hole by a deposition process or a plating process.

In some embodiments, the method of forming patterns in accordance withthe present inventive concepts may be implemented for the formation ofthe contact hole using the lower insulation layer 210 as an objectlayer.

The lower insulation layer 210 may be formed of an insulative materialsuch as silicon oxide or silicon oxynitride. For example, the lowerinsulation layer 210 may be formed of a silicon oxide-based materialsuch as plasma enhanced oxide (PEOX), tetraethyl orthosilicate (TEOS),boro tetraethyl orthosilicate (BTEOS), phosphorous tetraethylorthosilicate (PTEOS), boro phospho tetraethyl orthosilicate (BPTEOS),boro silicate glass (BSG), phospho silicate glass (PSG), boro phosphosilicate glass (BPSG), or the like.

The passivation layer 200 may be formed of silicon nitride. Theconductive layer may be formed of a metal such as aluminum (Al),tungsten (W) or copper (Cu), or a metal nitride.

In some embodiments, the lower contact 215 may be electrically connectedto a circuit device or a lower wiring formed on a semiconductorsubstrate. Damage of the circuit device or the lower wiring whileforming the contact hole may be prevented by the passivation layer 200.

A first etch-stop layer 220 may be formed on the lower insulation layer210 to cover the lower contacts 215. The first etch-stop layer 220 maybe formed of silicon nitride or silicon oxynitride. For example, thefirst etch-stop layer 220 may be formed by, e.g., a CVD process, a PECVDprocess, a spin coating process or an ALD process.

Referring to FIG. 8, an insulating interlayer 225, a buffer layer 230and a second etch-stop layer 235 may be sequentially formed on the firstetch-stop layer 220.

For example, the insulating interlayer 225 may be formed of theabove-mentioned silicon oxide-based material or a polysiloxane-basedmaterial. The buffer layer 230 and the second etch-stop layer 235 may beformed of, e.g., silicon oxynitride and silicon nitride, respectively. Astress generated from the second etch-stop layer 235 may be alleviatedand/or absorbed by the buffer layer 230.

The insulating interlayer 225, the buffer layer 230 and the secondetch-stop layer 235 may be formed by a CVD process, a PECVD process, asputtering process such as an ion beam sputtering process, a spincoating process, or the like.

Referring to FIG. 9, a photoresist layer 240 may be formed on the secondetch-stop layer 235.

The photoresist layer 240 may be formed using a photoresist compositionaccording to embodiments of the present inventive concepts. As describedabove, the photoresist composition may include a photoresist polymer anda solvent. The photoresist polymer may include a first repeating unitcontaining a halogen donor group and a second repeating unit containinga protecting group connected by a sulfide bond, which may be repeated ina backbone chain. The photoresist composition may optionally include aPAG. In some embodiments, the photoresist composition may optionallyinclude a sensitizer.

In some embodiments, the photoresist polymer may have a structure thatmay be represented by at least one of the above Chemical Formulae 1 to4.

The photoresist composition may be coated to form a preliminaryphotoresist layer, and the preliminary photoresist layer may be curedby, e.g., a baking process to form the photoresist layer 240.

Referring to FIG. 10, processes substantially the same as or similar tothose illustrated with reference to FIGS. 3 and 4 may be performed toform a photoresist pattern 250.

In some embodiments, an exposure process may be performed so that anactive halogen may be generated from the halogen donor group included inan exposed portion. The active halogen may be transferred to the sulfidebond. Thus, a polarity and/or a hydrophilicity of the exposed portionmay be increased by a photochemical reaction between the first andsecond repeating units.

In some embodiments, the buffer layer 230 may serve as ananti-reflective layer during the exposure process.

The exposed portion may be selectively removed by a developing processso that a photoresist pattern 250 may be formed.

Referring to FIG. 11, the second etch-stop layer 235, the buffer layer230, the insulating interlayer 225 and the first etch-stop layer 220 maybe partially and sequentially etched using the photoresist pattern 250as an etching mask. Thus, an opening 260 through which the lower contact215 may be exposed may be formed.

The opening 260 may be formed by a dry etching process. The opening 260may extend through the insulating interlayer 225 and the first etch-stoplayer 220, and may at least partially expose an upper surface of thelower contact 215.

In some embodiments, the opening 260 may have a contact hole shapethrough which each lower contact 215 may be exposed. In someembodiments, the opening 260 may have a linear shape through which aplurality of the lower contacts 215 may be exposed.

Referring to FIG. 12, a conductive layer 270 filling the openings 260may be formed.

In some embodiments, a barrier layer 265 may be formed conformally alongtop surfaces and sidewalls of the photoresist pattern 250, and sidewallsand bottoms of the openings 260. The conductive layer 270 may be formedon the barrier layer 265 to sufficiently fill the openings 260.

The barrier layer 265 may be formed of a metal nitride such as titaniumnitride, tantalum nitride or tungsten nitride. The barrier layer 265 mayprevent a metal ingredient in the conductive layer 270 from beingdiffused into the insulating interlayer 225. The barrier layer 265 mayalso provide an adhesion for the formation of the conductive layer 270.The barrier layer 265 may be formed by, e.g., a sputtering process or anALD process.

The conductive layer 270 may be forming by, e.g., an electroplatingprocess. In this case, a seed layer may be formed conformally on thebarrier layer 265 by a sputtering process using a copper target. Aplating solution such as a copper sulfate solution may be prepared, anda current may be applied using the seed layer and the plating solutionas a cathode and an anode, respectively. Thus, the conductive layer 270including copper may be grown or precipitated on the seed layer throughan electrochemical reaction.

In some embodiments, the conductive layer 270 may be deposited by asputtering process using a metal target such as copper, tungsten oraluminum, or an ALD process.

Referring to FIG. 13, upper portions of the conductive layer 270 and thebarrier layer 265 may be planarized to form a conductive pattern 280.

In some embodiments, the upper portions of the conductive layer 270 andthe barrier layer 265 may be planarized by a CMP process until a topsurface of the insulating interlayer 225 is exposed. The photoresistpattern 250, the second etch-stop layer 235 and the buffer layer 230 maybe also removed by the planarization process.

Accordingly, the conductive pattern 280 electrically connected to thelower contact 215 may be formed in the opening 260. The conductivepattern 280 may include a barrier layer pattern 267 formed on thesidewall and the bottom of the opening 260, and a conductive layerpattern 275 filling a remaining portion of the opening 260 on thebarrier layer pattern 267.

FIGS. 12 and 13 illustrate that the photoresist pattern 250 may beremoved by a planarization process for the formation of the conductivepattern 280. However, the photoresist pattern 250 may be removed afterforming the opening 260 and before forming the barrier layer 265. Forexample, after forming the opening 260, the photoresist pattern 250 maybe removed by an ashing process and/or a strip process.

In some embodiments, a cleaning process may further be performed toremove an etching residue including, e.g., a metal which may remain onthe insulating interlayer 225.

Referring to FIG. 14, a capping layer pattern 290 may be formed on anupper surface of the conductive pattern 280.

For example, a capping layer covering the conductive patterns 280 may beformed on the insulating interlayer 225, and the capping layer may bepartially etched to form the capping layer pattern 290 which may coverthe conductive pattern 280.

The capping layer may be formed of a metal that may be more chemicallystable than a metal included in the conductive pattern 280 by asputtering process or an ALD process. For example, the capping layer maybe formed using a metal such as aluminum, cobalt or molybdenum. In someembodiments, the capping layer may be formed of a nitride of the metal.

The capping layer may be patterned by a wet etching process using anetchant solution that may include peroxide such as hydrogen peroxide.

In some embodiments, a build-up process may be further performed suchthat additional insulating interlayer, conductive pattern and/or upperwiring may be formed on the insulating interlayer 225 and the cappinglayer pattern 290. In this case, the conductive pattern 280 may serve asan interconnection structure electrically connecting the lower contact215 and the upper wiring to each other. In some embodiments, theconductive pattern 280 may serve as a wiring extending linearly, and maybe electrically connected to the plurality of the lower contacts 215.

As described above, the opening 260 for the formation of the conductivepattern 280 may be formed using the photoresist polymer or thephotoresist composition according to example embodiments.

As a width of the conductive pattern 280 and a distance betweenconductive patterns 280 decreases, a photolithography process havinghigh resolution may be needed. In some embodiments, an exposure processmay be performed only through a photochemical reaction between theactive halogen and the protecting group including the sulfide bond.Thus, an irregular acid diffusion occurring in a CAR system-basedphotolithography process may be avoided. Therefore, the conductivepattern having a fine pitch and a fine dimension may be formed as adesired uniform profile, and a resolution of the photolithographyprocess may be improved.

Methods of Manufacturing Semiconductor Devices

FIGS. 15 to 25 are top plan views and cross-sectional views illustratinga method of manufacturing a semiconductor device according to thepresent inventive concepts.

Specifically, FIGS. 15 and 19 are top plan views illustrating a methodof manufacturing a semiconductor device. FIGS. 16 to 18, and FIGS. 20 to25 are cross-sectional views illustrating the method of manufacturingthe semiconductor device. Each of FIGS. 16 to 18, and FIGS. 20 to 25includes sub-cross sectional views taken along lines I-I′ and II-II′indicated in FIGS. 15 and 19.

For example, FIGS. 15 to 25 illustrate a method of manufacturing asemiconductor device including a buried cell array transistor (BCAT)structure.

Two directions perpendicular to each other are referred to as a firstdirection and a second direction. The first and second directions areparallel to a top surface of a substrate. Additionally, a directionindicated by an arrow and a reverse direction thereof are considered asthe same direction.

Referring to FIGS. 15 and 16, active patterns 305 and an isolation layer302 may be formed at an upper portion of a substrate 300, and gatestructures 318 extending in the active patterns 305 may be formed.

The substrate 300 may include silicon, germanium, silicon-germanium or agroup III-V compound such as GaP, GaAs, or GaSb. In some embodiments,the substrate 300 may be an SOI substrate or a GOI substrate.

In example embodiments, the isolation layer 302 and the active patterns305 may be formed by a shallow trench isolation (STI) process. Forexample, an upper portion of the substrate 300 may be partially removedby an anisotropic etching process to form an isolation trench. Aninsulation layer filling the isolation trench and including, e.g.,silicon oxide may be formed on the substrate 300. An upper portion ofthe insulation layer may be planarized by, e.g., a CMP process until atop surface of the substrate 300 is exposed to form the isolation layer302.

A plurality of the active patterns 305 may be formed to be spaced apartfrom each other by the isolation layer 302. As illustrated in FIG. 15,each active pattern 305 may extend in a diagonal direction to the firstdirection or the second direction at a given angle. The plurality of theactive patterns 305 may be arranged in the first and second directions.

Upper portions of the active patterns 305 and the isolation layer 302may be etched to form gate trenches 309, and the gate structure 318 maybe formed in each gate trench 309.

For example, the gate trenches 309 may extend in the first direction,and a plurality of the gate trenches 309 may be formed along the seconddirection. In some embodiments, two of the gate trenches 309 may beformed at one of the active patterns 305.

In some embodiments, the gate trench 309 may be formed by a method offorming patterns in which the photoresist polymer or the photoresistcomposition according to the present inventive concepts may be used.

For example, a photoresist composition including a photoresist polymerthat may contain first and second repeating units as described above maybe coated on the active pattern 305 and the isolation layer 302 to forma photoresist layer. A portion of the photoresist layer overlapping thegate trench 309 may be modified into an exposed portion having increasedpolar and/or hydrophilic properties by an exposure process. The exposedportion may be removed by a developing process to form a photoresistpattern. Upper portions of the active pattern 309 and the isolationlayer 302 may be etched using the photoresist pattern as an etching maskto form the gate trench 309.

Subsequently, a gate insulation layer 312 and a gate electrode 314filling a lower portion of the gate trench 309 may be formed. A gatemask 316 capping the gate trench 309 may be formed on the gateinsulation layer 312 and the gate electrode 314.

For example, the gate insulation layer 312 may be formed by a thermaloxidation process on a surface of the active pattern 305 exposed by thegate trench 309, or by depositing silicon oxide or a metal oxidethrough, e.g., a CVD process.

A gate conductive layer filling a remaining portion of the gate trench309 may be formed on the gate insulation layer 312. The gate conductivelayer may be planarized by a CMP process until the top surface of theactive pattern 305 is exposed, and upper portions of the gate insulationlayer 312 and the gate conductive layer may be removed by an etch-backprocess. Accordingly, the gate insulation layer 312 and the gateelectrode 314 filling the lower portion of the gate trench 309 may beformed.

The gate conductive layer may be formed using a metal and/or a metalnitride by an ALD process or a sputtering process.

A mask layer filling a remaining portion of the gate trench 309 may beformed on the gate insulation layer 312 and the gate electrode 314, andan upper portion of the mask layer may be planarized until the topsurface of the active pattern 305 is exposed to form the gate mask 316.The mask layer may be formed of silicon nitride by, e.g., a CVD process.

Accordingly, a gate structure 318 including the gate insulation layer312, the gate electrode 314 and the gate mask 316, that may besequentially stacked in the gate trench 309, may be formed.

According to an arrangement of the gate trenches 309, a plurality of thegate structures 318 may be formed to be arranged along the seconddirection and each gate structure 318 may extend in the first direction.The gate structure 318 may be buried or embedded in the active pattern305. An upper portion of the active pattern 305 may be divided into acentral portion between two gate structures 318, and a peripheralportion (or end portions) facing the central portion with respect toeach of the gate structures 318.

An ion-implantation process may be performed to form a first impurityregion 301 and a second impurity region 303 at upper portions of theactive pattern 305 adjacent to the gate structures 318. For example, thefirst impurity region 301 may be formed at the central portion of theactive pattern 305, and the second impurity region 303 may be formed atthe peripheral portions of the active pattern 305.

In some embodiments, as illustrated in FIG. 16, an upper portion of theisolation layer 302 may be recessed by an etch-back process such thatthe upper portion of the active pattern 305 may be exposed.Subsequently, the ion-implantation process may be performed to form thefirst and second impurity regions 301 and 303.

A capping layer 320 covering the active patterns 305 and the isolationlayer 302 may be formed, and a first insulating interlayer 325 may beformed on the capping layer 320. For example, the capping layer 320 andthe first insulating interlayer 325 may be formed of silicon nitride andsilicon oxide, respectively. The capping layer 320 may substantiallyserve as an etch-stop layer during subsequent etching processes.

Referring to FIG. 17, the first insulating interlayer 325 and thecapping layer 320 may be sequentially and partially etched to form agroove 327 through which the first impurity regions 301 may be exposed.The groove 327 may extend in the second direction indicated in FIG. 15,and a plurality of the grooves 327 may be formed to be arranged alongthe first direction.

In some embodiments, an upper portion of the first impurity region 301may be partially removed during the etching process for the formation ofthe groove 327. Accordingly, a height difference may exist between thefirst and second impurity regions 301 and 303, and thus a bridge or ashort circuit between a conductive line structure 345 and a conductivecontact 375 (see FIG. 25) formed by subsequent processes may beprevented.

Referring to FIG. 18, a first conductive layer 330 filling the groove327 may be formed on the first insulating interlayer 325. A barrierconductive layer 335 and a second conductive layer 337 may besequentially formed on the first conductive layer 330, and a maskpattern 340 may be formed on the second conductive layer 337.

For example, the first conductive layer 330 may be formed using dopedpolysilicon, the barrier conductive layer 335 may be formed of a metalnitride or a metal silicide nitride, and the second conductive layer 337may be formed using a metal. The first conductive layer 330, the barrierconductive layer 335 and the second conductive layer 337 may be formedby, e.g., a sputtering process, a PVD process, CVD process, or an ALDprocess.

The mask pattern 340 may include, e.g., silicon nitride, and may extendin the second direction. A width of the mask pattern 340 (e.g., a widthin the first direction) may be smaller than that of the groove 327.

In some embodiments, the mask pattern 340 may be formed by a method offorming patterns in which a photoresist polymer or a photoresistcomposition according to the present inventive concepts may be used.

For example, a mask layer including silicon nitride may be formed on thesecond conductive layer 337. A photoresist composition including aphotoresist polymer that may contain first and second repeating units asdescribed above may be coated on the mask layer to form a photoresistlayer. A portion of the photoresist layer overlapping the mask pattern340 may be modified into an exposed portion having increased polarand/or hydrophilic properties by an exposure process. The exposedportion may be removed by a developing process to form a photoresistpattern. The mask layer may be etched using the photoresist pattern asan etching mask to form the mask pattern 340.

Referring to FIGS. 19 and 20, the second conductive layer 337, thebarrier conductive layer 335 and the first conductive layer 330 may besequentially etched using the mask pattern 340 as an etching mask.Accordingly, a first conductive layer pattern 332, a barrier conductivelayer pattern 336 and a second conductive layer pattern 338 may besequentially formed on the first impurity region 301. For convenience ofdescriptions, illustrations of the first insulating interlayer 325 andthe capping layer 320 are omitted in FIG. 19.

Accordingly, the conductive line structure 345 including the firstconductive layer pattern 332, the barrier conductive layer pattern 336,the second conductive layer pattern 338 and the mask pattern 340 may beformed. The conductive line structure 345 may extend in the seconddirection on the first impurity region 301. In example embodiments, theconductive line structure 345 may serve as a bit line.

In some embodiments, the conductive line structure 345 may have anarrower width that that of the groove 327. Thus, a sidewall of theconductive line structure 345 may be spaced apart from a sidewall of thegroove 327.

Referring to FIG. 21, a spacer 347 may be formed on a sidewall of theconductive line structure 345. For example, a spacer layer covering theconductive line structure 345 may be formed on the first insulatinginterlayer 325. The spacer layer may be anisotropically etched to formthe spacer 347. The spacer layer may be formed of, e.g., siliconnitride.

A second insulating interlayer 350 covering the conductive linestructure 345 may be formed on the first insulating interlayer 325. Thesecond insulating interlayer 350 may fill a remaining portion of thegroove 327.

In some embodiments, an upper portion of the second insulatinginterlayer 350 may be planarized by a CMP process such that a topsurface of the mask pattern 340 may be exposed. The second insulatinginterlayer 350 may be formed of silicon oxide substantially the same asor similar to that of the first insulating interlayer 325.

Referring to FIG. 22, a buffer layer 355 may be formed on the secondinsulating interlayer 350 and the mask pattern 340, and a photoresistlayer 360 may be formed on the buffer layer 355.

The buffer layer 355 may substantially serve as a passivation layer oran anti-reflective layer. For example, the buffer layer 355 may beformed using an aromatic organic composition such as a phenol resin or anovolak resin, or an inorganic material such as silicon oxynitride. Inan embodiment, the formation of the buffer layer 355 may be omitted.

The photoresist layer 360 may be formed using a photoresist compositionin accordance with the present inventive concepts. As described above,the photoresist composition may include a photoresist polymer and asolvent. The photoresist polymer may include a first repeating unitcontaining a halogen donor group and a second repeating unit containinga protecting group connected by a sulfide bond, which may be repeated ina backbone chain. The photoresist composition may optionally include aPAG. In some embodiments, the photoresist composition may optionallyinclude a sensitizer.

In some embodiments, the photoresist polymer may include a structurethat may represented by at least one of the above Chemical Formulae 1 to4.

The photoresist composition may be coated to form a preliminaryphotoresist layer, and then a curing process such as a baking processmay be performed to form the photoresist layer 360.

Referring to FIG. 23, processes substantially the same as or similar tothose illustrated with reference to FIGS. 3 and 4 may be performed toform a photoresist pattern 365.

In example embodiments, an exposure process may be performed so that anactive halogen may be generated from a halogen donor group included inan exposed portion. The active halogen may be transferred to a sulfidebond present in the exposed portion. Thus, a polarity and/or ahydrophilicity of the exposed portion may be increased by aphotochemical reaction between moieties in the first and secondrepeating units of a photoresist polymer.

The exposed portion may be selectively removed by a developing processso that the photoresist pattern 365 may be formed. The photoresistpattern 365 may include a plurality of openings corresponding to holeformation areas 357 indicated in FIG. 19.

Referring to FIG. 24, the buffer layer 355, the second insulatinginterlayer 350, the first insulating interlayer 325 and the cappinglayer 320 may be partially etched using the photoresist pattern 365 asan etching mask. Accordingly, a contact hole 370 may be formed, whichmay at least partially expose the second impurity region 303. Thecontact hole 370 may be formed per each of hole formation areas 357indicated in FIG. 19.

The photoresist pattern 365 and the buffer layer 355 may be removed by aCMP process, an ashing process and/or a strip process after theformation of the contact hole 370

Referring to FIG. 25, the conductive contact 375 filling the contacthole 370 and electrically connected to the second impurity region 303may be formed. For example, a capacitor 390 may be formed on theconductive contact 375. In this case, the conductive contact 375 mayserve as a capacitor contact.

For example, a conductive layer filling the contact holes 370 may beformed, and an upper portion of the conductive layer may be planarizedby a CMP process until the top surface of the mask pattern 340 isexposed. Accordingly, the conductive contact 375 may be formed in eachcontact hole 370, and may be in contact with the second impurity region303.

The conductive layer may be formed using a metal such as copper ortungsten by a sputtering process, a PVD process, an ALD process, or aCVD process. In some embodiments, the conductive layer may be formed byan electroplating process or an electrolessplating process. In someembodiments, a barrier conductive layer including, e.g., titanium ortitanium nitride may be formed on an innerwall of the contact hole 370before forming the conductive layer.

The capacitor 390 electrically connected to the conductive contact 375may be formed. Thus, a dynamic random access memory (DRAM) device havingthe BCAT structure may be achieved.

For example, an etch-stop layer and a mold layer (not illustrated) maybe formed on the mask pattern 340, the second insulating interlayer 350and the conductive contact 375. The mold layer and the etch-stop layermay be partially removed to form a capacitor opening through which a topsurface of the conductive contact 375 is exposed.

A lower electrode layer may be formed along an innerwall of thecapacitor opening and a top surface of the mold layer. The lowerelectrode layer may be formed of a metal or a metal nitride. Forexample, the lower electrode layer may be formed of at least one oftungsten, tungsten nitride, titanium, titanium nitride, tantalum,tantalum nitride and/or ruthenium. A sacrificial layer (not illustrated)may be formed on the lower electrode layer, and upper portions of thesacrificial layer and the lower electrode layer may be planarized suchthat the top surface of the mold layer is exposed. The sacrificial layerand the mold layer may be removed to form a lower electrode 380.

A dielectric layer 385 may be formed on surfaces of the etch-stop layerand the lower electrode 380, and an upper electrode 387 may be formed onthe dielectric layer 385 to form the capacitor 390. The dielectric layer385 may be formed of silicon oxide or a metal oxide having a highdielectric constant. The upper electrode 387 may be formed of a metal ora metal nitride substantially the same as or similar to that of thelower electrode 380.

In some embodiments, a magnetic tunnel junction (MTJ) structure may beformed on the conductive contact 375. In this case, the semiconductordevice may serve as a magnetic random access memory (MRAM) device havingthe BCAT structure.

For example, a fixed layer, a tunnel barrier layer and a tunnel barrierlayer interposed therebetween may be formed on the mask pattern 340, thesecond insulating interlayer 350 and the conductive contact 375. Thefixed layer and the free layer may be formed of a magnetic material. Thetunnel barrier layer may be formed of, e.g., at least one of magnesiumoxide, titanium oxide, aluminum oxide, magnesium zinc oxide andmagnesium boron oxide.

The free layer, the tunnel barrier layer and the fixed layer may bepartially etched to form the MTJ structure on each conductive contact375. In some embodiments, the etching process for the free layer, thetunnel barrier layer and the fixed layer may include a photolithographyprocess or a method of forming patterns in which the photoresistcomposition or the photoresist polymer according to the presentinventive concepts may be utilized.

According to example embodiments as described above, in a manufacture ofa semiconductor device including, e.g., the BCAT structure, an exposureprocess based on a photochemical reaction between the active halogen andthe protecting group including the sulfide bond may be performed insteadof an exposure process based on a CAR system generating a large amountof acid. Thus, a reduction of resolution and a mis-alignment of, e.g.,the contact holes 370 caused by an acid diffusion may be avoided.

The photoresist composition or the photoresist polymer in accordancewith example embodiments may be used in a photolithography process for aformation of a fine pattern having a dimension of, e.g., about 20 nm.Wirings, contacts, insulation patterns, etc., of various semiconductordevices such as DRAM or MRAM devices may be formed by thephotolithography process with high resolution and reliability.

The foregoing is illustrative of the present inventive concepts and isnot to be construed as limiting thereof. Although a few exampleembodiments have been described, those skilled in the art will readilyappreciate that many modifications are possible in the exampleembodiments without materially departing from the novel teachings andadvantages of the present inventive concepts. Accordingly, all suchmodifications are intended to be included within the scope of thepresent inventive concepts. Therefore, it is to be understood that theforegoing is illustrative of various example embodiments and is not tobe construed as limited to the specific example embodiments disclosed,and that modifications to the disclosed example embodiments, as well asother example embodiments, are intended to be included within the scopeof the present inventive concepts as well as the appended claims.

1.-37. (canceled)
 38. A photoresist polymer, comprising: a firstrepeating unit including a halogen donor group; and a second repeatingunit including a leaving group capable of being removed by aphotochemical reaction, the leaving group being connected to the secondrepeating unit by a sulfide bond.
 39. The photoresist polymer of claim38, wherein the halogen donor group includes a heterocyclic compoundhaving a nitrogen-halogen bond.
 40. The photoresist polymer of claim 39,wherein the halogen donor group includes at least one moiety selectedfrom N-iodosuccinimide (NIS), N-bromosuccinimide (NBS),N-chlorosuccinimide (NCS), N-iodophthalimide (NIPI), N-bromophthalimide(NBPI) and N-chlorophthalimide (NCPI).
 41. The photoresist polymer ofclaim 38, wherein the polymer includes a structure that is representedby Chemical Formula 1 or Chemical Formula 2:

wherein, in Chemical Formulae 1 and 2, R₁ and R₄ are each independentlya divalent group selected from styrene, hydroxystyrene, acrylate, C₁-C₆alkylene, arylene, carbonyl, oxy, C₆-C₃₀ aliphatic ester, C₆-C₃₀unsaturated aliphatic group or a combination thereof, R₂ is hydrogen ora C₁-C₂₀ alkyl group, R₃ is a C₆-C₃₀ aromatic group or a C₁-C₂₀ alkylgroup, X represents chlorine (Cl), bromine (Br) or iodine (I), and eacha and b represents a mole ratio in a range of about 0.4 to about 0.6,and a sum of a and b is
 1. 42. The photoresist polymer of claim 41,wherein the polymer includes a structure that is represented by ChemicalFormula 3 or Chemical Formula 4:

wherein, in Chemical Formulae 3 and 4, n is an integer in a range of 100to 10,000.
 43. A photoresist composition, comprising: a photoresistpolymer comprising a first repeating unit including a halogen donorgroup, and a second repeating unit including a leaving group capable ofbeing removed by a photochemical reaction, the leaving group beingconnected to the second repeating unit by a sulfide bond; and a solvent.44. The photoresist composition of claim 43, wherein the polymerincludes a structure that is represented by Chemical Formula 1 orChemical Formula 2:

wherein, in Chemical Formulae 1 and 2, R₁ and R₄ are each independentlya divalent group selected from styrene, hydroxystyrene, acrylate, C₁-C₆alkylene, arylene, carbonyl, oxy, C₆-C₃₀ aliphatic ester, C₆-C₃₀unsaturated aliphatic group or a combination thereof, R₂ is hydrogen ora C₁-C₂₀ alkyl group, R₃ is a C₆-C₃₀ aromatic group or a C₁-C₂₀ alkylgroup, X represents chlorine (Cl), bromine (Br) or iodine (I), and eacha and b represents a mole ratio in a range of about 0.4 to about 0.6,and a sum of a and b is
 1. 45. The photoresist composition of claim 43,further comprising a photoacid generator.